Baking oven construction

ABSTRACT

An oven construction wherein the oven wall forms an oven cavity containing in a lower portion thereof a HTA producing device, wherein a steam generator is provided in the cavity in physically isolated relationship to the device, wherein the steam generator contains a plurality of metal balls which act as a heat sink, and wherein a water reservoir is provided on the outside of the oven and is in water flow communication with the steam generator thru a water feed line.

[0001] This application claims priority under 35 U.S.C. 119(e)(1) basedon Applicant's Provisional U.S. Patent Application Serial No.60/350,521, filed Oct. 25, 2001 and titled “Baking Oven SteamGenerator”.

BACKGROUND OF THE INVENTION

[0002] 1. Field

[0003] This invention concerns the modification of ovens, primarily ofthe rack type such as are used in homes, but also is useful incommercial size ovens, wherein the present modifications effect a uniquehot air circulation pattern and, in a most preferred embodiment alsofeatures a conveniently located and easy to use unique steam generator.The present heated air circulation pattern dramatically improves theoven baking quality and efficiency and the generator provides limitedbursts of steam to the oven in an improved manner to assist, e.g., informing a thick, ruddy brown, crisp crust to bread particularly Frenchbread being baked.

[0004] 2. Prior Art

[0005] U.S. Pat. No. 5,680,810, the disclosure of which is herebyincorporated herein by reference in its entirety, discloses a radiantheat toaster oven provided with a steam generating system wherein awater filled tube is placed into contact with an electrical heatingelement whereby the water is brought to a boil and stem is allowed toescape thru vent holes in the tube.

SUMMARY OF THE INVENTION

[0006] The present oven in one preferred embodiment comprises wall meansforming a substantially closed cavity means having an upper portion anda lower portion, HTA (high temperature air) supply means mounted in saidlower portion of said cavity means for generating a rising HTA flowwithin said cavity means, and air flow outlet means thru a lower sectionof said wall means, whereby said HTA from said supply means will riseinto said upper portion of said cavity means and then as it becomescooler will gravitate downwardly into said lower portion of said cavitymeans and exit thru said outlet means, whereby said HTA will be forcedto travel a longer residence path within said cavity means and release alarger amount of heat energy into said cavity means prior to dischargeof said HTA therefrom.

[0007] In another preferred embodiment a steam generator means ismounted in said cavity means and comprises water inlet means, heat sinkmeans, steam outlet means, water reservoir means mounted on the exteriorof said wall means on an upper portion thereof, and water feed linemeans passing thru said wall means and into said cavity means and havingone end connected to said reservoir means and having its other endjuxtaposed said inlet means, whereby a measured amount of water can bepoured into said reservoir means and conducted thru said feed line meansinto said inlet means and into contact with said heat sink means toproduce a desired amount of steam.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present oven, in its preferred structural embodiments, isshown in FIGS. 1-13 wherein the scale and dimensions of the oven andsteam generator components are shown for illustration of the inventiononly and are not intended to represent commercial ovens proportionatelyin size or configuration, wherein equivalent structure in the figuresare numbered the same, and wherein;

[0009]FIG. 1 is a front view of an oven with portions of the oven frontand door, and the steam generator broken away for clarity;

[0010]FIG. 2 is a side view taken along line 2-2 of FIG. 1 with portionsbroken away for clarity;

[0011]FIG. 3 is a cross sectional view taken along line 3-3 of FIG. 1;

[0012]FIG. 4 is a cross-sectional view as in FIG. 2 but showing apreferred positioning of the steam generator with respect to the ovenheating element;

[0013]FIG. 5 is an isometric schematic of a portion of the oven interiorshowing preferred locations of the steam generator, water feed tube andwater reservoir;

[0014]FIG. 6 is an isometric top view of a preferred steam generatortube;

[0015]FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6 inthe direction of the arrows;

[0016]FIG. 8 is an isometric view of an upright tube steam generatorwith portions broken away for clarity;

[0017]FIG. 9 is a front view of an oven with the front door and thefront of the burner housing removed to show a preferred position for thesteam generator of FIG. 8; .

[0018]FIG. 10 is a front view of an oven with the door removed to showhow the steam generator feed tube is mounted to enter into the ovencavity;

[0019]FIG. 11 is an enlarged cross-sectional view taken along line 11-11of FIG. 10;

[0020]FIG. 12 is a front view of a gas fired oven wherein the variousstructural components are approximately drawn to scale but withthickness enlarged for clarity, with the door removed and showing apreferred form of steam generator and a preferred positioning of theheated air exhaust or discharge vents; and

[0021]FIG. 13 is a cross-sectional view taken along line 13-13 of FIG.12.

DETAILED DESCRIPTION

[0022] Referring to the drawings, a typical home oven 10 is shown ashaving an oven cavity means 49 formed by wall 11 which is spaced fromouter wall 12 of the oven cabinet generally designated 23 for heatinsulation whereby wall 11 provides a lower high heat portion 13 and anupper cooler air portion 21 in the cavity means 49. Provided for theoven are the structures of an oven door 14 conventionally hinged at thelower portion 16 of wall 12, a control panel 17 with control knobs 19 atthe upper portion 18 of wall 12, and a loop-like electrical heatingelement 20 having its power/ground electrical connection ends 22, 24inserted thru the rear or back portion 15 of cavity wall 11. Footmembers 28 keep the heating element elevated a short distance above theoven floor or baffle plate means 30. Cabinet 23 as shown in FIGS. 12 and13 has a front portion 68, sides 69, back wall 71 and top 73.

[0023] The present steam generator generally designated 31, in oneembodiment, comprises a stainless steel open top body 32 having a thickbase or flash pan 34, i.e., about ½ in. thick which functions also as aheat sink. A useful set of dimensions for body 32 is about 3 in. outsideheight, about 8 in. long on the inside, and about 3 in. wide on theinside. These dimensions can vary depending how much water one wishes toflash into steam and how fast.

[0024] The water is poured as needed into a reservoir 36 of, e.g., about4-8 oz. capacity, preferably mounted on the front of wall portion 18 andis conducted thru a small metal tube or line 38 such as a ⅛ in. I.D.copper or stainless steel tubing. This line is affixed to the inside ofwall 12 and runs, as shown, into the open top of body 32 withoutcontacting heating element 20. The inlet end 41 or outlet end 42 of line38 can be pinched as desired to feed the water onto flash pan 34 at adesired rate.

[0025] Referring to FIGS. 4-7, a much preferred steam generating body 44preferably of tubular stainless steel pipe of, e.g., 1½ in. I.D. and 9in. length, capped at both ends is employed and is provided with holes46, one of which connects with outlet end 42 of line 38 and the othersallowing the escape of steam. A bed 48 of ⅛″ to ½″, preferably ¼″diameter stainless steel balls is positioned in the tube to provide amass to capture sufficient heat prior to introduction of water to flashthe water from the tube when needed.

[0026] The position of the generator as shown in FIG. 5 within the ovencavity 49 is quite significant in that it is juxtaposed but not touchingthe heating element 20 so that the generator is maximally effective inabsorbing radiant heat but doesn't block the heating element such as tocause a cold spot in the oven.

[0027] Referring to FIGS. 8 and 9 concerning a gas fired oven having gasburners 39, this particular embodiment 50 of the steam generatorcomprises a substantially vertically mounted tube 52 of about 12 in. inlength, preferably stainless steel, schedule 40, having a top inlet pipe54 connected to feed line 38 extending into tube 52 about, e.g., 1½ in.,having a plurality of slots 56 of about, e.g., ¾ in. length and{fraction (3/16)} in. width spaced, e.g., 30 degrees around the tube,and being welded to sides 58 of bracket 60.

[0028] The tube 52 is filled with, e.g., ¼ in, diameter stainless steelballs 62, preferably up to just below the inner end 55 of pipe 54.Bracket 60 is mounted, e.g., by welding to the oven base plate or floor30 such that tube 52 is directly in the path of the HTA rising fromburner chamber 63 thru inlet 64 into oven cavity 49. After circulationof the heated air in cavity 49 it is discharged to the atmosphere thrudischarge vents such as 51 thru the back portion 84 of wall 11.

[0029] In FIGS. 10 and 11 the structure of the entry of water feed line38 into oven cavity 49 is shown as simply interposing a generallylaterally oriented section 66 of the line between a front portion 68 ofthe oven housing and a conventional compressible seal member 70 which isaffixed to the oven door 14 so as to substantially heat and air seal theoven access opening generally designated 72 when the door is shutagainst the oven housing front. This seal 70 is sufficientlycompressible to easily conform around line section 66 to maintain a goodheat and air seal when the oven door is closed.

[0030] Referring to FIGS. 12 and 13, a very efficient gas fired ovenconstruction is shown and comprises individually and/or in combination aunique heated air flow pattern and structure within the oven and aunique steam generator structure. The steam generator comprises a platemember which preferably is the oven floor 30 formed with a recess suchas 74 which can be V shaped or concavely curved or the like and whichcan extend for any desired length along the floor, preferably laterallybetween the gas burners 39 located below the floor 30 in burner chamber63. This recess should be dimensioned to hold a substantial quantity ofsteel balls or the like, preferably at least about two pounds for atypical home use oven.

[0031] The HTA from the burner chamber enters into the oven cavity 49thru ports 76 in floor 30 of any selected size and number, and fresh airis fed into the burner chamber thru suitable vents such as 78 in theburner chamber floor 80. In this preferred construction, the heated airdischarge vents 82 are provided thru the back portion 84 of wall 11,substantially adjacent the bottom thereof, e.g., starting 1-6 inchesfrom floor 30, for venting to the atmosphere. Preferably, vent ductssuch as 85 are provided to direct the exhaust air to a desirable ventlocation such as louvered openings 86 to the atmosphere. This locationof the vents 82 ensures that the upward HTA flow and the downward coolerair flow will be forced into a generally circular flow patternsubstantially as indicated by the flow arrows in FIG. 12.

[0032] This airflow pattern reduces the heat up time for achieving abaking temperature of, e.g., about 450° F. from about 43 minutes toabout 19 minutes and markedly improves the evenness of temperaturethroughout the oven with or without the use of convection fans. Also,when a steam generator is employed with this unique air flow pattern,more steam is trapped within the oven cavity for a longer period of timewhich results in more efficient heating in the oven which greatlyreduces the duration of the gas burn periods and the bum frequency, andcourse also reduces the cost of operating the oven.

[0033] This invention has been described in detail with particularreference to preferred embodiments thereof, but it will be understoodthat variations and modifications will be effected within the spirit andscope of the invention.

I claim:
 1. Oven construction comprising first wall means forming asubstantially closed oven cabinet, second wall means forming asubstantially closed oven cavity means having an upper portion and alower portion, HTA supply means mounted in said lower portion of saidcavity means for generating a rising HTA flow within said cavity means,and air flow outlet means formed thru a lower section of said secondwall means, whereby said HTA from said supply means will rise into saidupper portion of said cavity means and then as it becomes cooler willgravitate downwardly into said lower portion of said cavity means andexit thru said outlet means, whereby said HTA will be forced to travel alonger residence path within said cavity means and release a largeramount of heat energy into said cavity means prior to discharge of saidHTA therefrom.
 2. The oven construction of claim 1 wherein a steamgenerator means is mounted in said cavity means and comprises waterinlet means, heat sink means, steam outlet means, water reservoir meansmounted on the exterior of said first wall means on an upper portionthereof, and water feed line means passing thru said first and secondwall means and into said cavity means and having one end connected tosaid reservoir means and having its other end juxtaposed said inletmeans, whereby a measured amount of water can be poured into saidreservoir means and conducted thru said feed line means into said inletmeans and into contact with said heat sink means to produce a desiredamount of steam within said cavity means.
 3. The oven construction ofclaim1 wherein said HTA supply means comprises a gas burnerinstallation.
 4. The oven construction of claim 3 wherein said outletmeans are in air flow communication with air flow duct means whichextend upwardly from said outlet means to adjacent the top portion of aback wall of said first wall means of said oven cabinet, and whereinvent openings are provided in said top portion and are in air flowcommunication with said duct means to vent gas combustion exhaust gases.5. The oven construction of claim 4 wherein baffle plate means ismounted in said cavity means to substantially separate said gas burnerinstallation from the remainder of said cavity means, wherein said heatsink means comprises a recess indention, in said baffle plate means, andwherein a plurality of metal pieces are contained in said indentation.6. The oven construction of claim 5 wherein said metal pieces arestainless steel balls.
 7. The oven construction of claim 1 wherein saidHTA supply means comprises an electrical heating element.
 8. Ovenconstruction comprising first wall means forming a substantially closedoven cabinet, second wall means forming a substantially closed ovencavity means having an upper portion and a lower portion, HTA supplymeans mounted in said lower portion of said cavity means for generatinga rising HTA flow within said cavity means steam generator means mountedin said cavity means and comprising water inlet means, heat sink means,steam outlet means, water reservoir means mounted on the exterior ofsaid first wall means on an upper portion thereof, and water feed linemeans passing thru said first and second wall means and into said cavitymeans and having one end connected to said reservoir means and havingits other end juxtaposed said inlet means, whereby a measured amount ofwater can be poured into said reservoir means and conducted thru saidfeed line means into said inlet means and into contact with said heatsink means to produce a desired amount of steam within said cavitymeans.
 9. The oven construction of claim 8 wherein said HTA supply meansis an electrical heating element.
 10. The oven construction of claim 3wherein said steam generator means is mounted in said cavity meansdirectly within the upwardly directed HTA flow from the gas burnerinstallation.